Protractor-rule.



PATENTED AUG. 18, 1903.

A. PETERSON. PROTRACTOR RULE.

APPLICATION FILED FEB. 4. 1903.

N0 MODEL.

F lwwen tor:

Witnesses:

W /zad /a gm a Patented August 18, 1903.

ALBERT PETERSON, OF BROOKTON, MASSACHUSETTS.

PROTRACTOR-RU LE.

SPECIFICATION forming part of Letters Patent No. 736,437, dated August 18, 1903. Application filed February 4, 1903. Serial No. 141,824. (No model.)

To 40% whom it may concern;

Be it known that I, ALBERT PETERSON, a citizen of the United States, and a resident of Brockton, in the county of Plymouth and State of Massachusetts, have invented certain new and useful Improvements in Protractor- Rules, of which the following is a specification.

This invention relates to the combination, with a hinged rule, of means for adjusting and securing the legs of such rule in various positions for the purpose of laying out or measuring angles, as will hereinafter bemore fully shown and described, reference being had to the accompanying drawings,wherein Figure l is aside elevation of the invention, showing the hinged legs of the rule secured in position for measuring a right angle. Fig. 2 is an edge View of Fig. 1. Fig. 3 is a detail sectional view showing a portion of the rule and the pivoted link guided therein. Fig. 4 is a longitudinal section on the line 4 4. shown in Fig. 3; and Fig. 5 is a side elevation of the rule, showing its legs closed and showing a portion broken away for the better illustration of the construction of the device.

Similar letters refer to similar parts wherever they occur on the different parts of the drawings.

A and B represent the respective legs of a measuring-rule pivoted together at (3,as usual. To the legAis pivoted aid) the link or blade E, which is provided on its inner edge with notches or recesses e e e for a purpose as will hereinafter be described. In the legA is made an edge recess A,adapted to receive the blade E when the legs A B are closed together, as shown in Fig. 5. In practice I make on the end of the blade E a projection e, (shown in Figs. 1 and 5,) which may readily be picked by the thumb or finger nail whenever it is desired to swing the blade E into position for using the device as a protractor. At other times the device has the general appearance of an ordinary two-foot rule, as shown in Fig. 5.

In the leg B isagroove or recess B',through which isguided the blade E, as shown in Fig. 3. Said recess or groove B is covered by a metal plate F, through which is screwed a binder-screw G, by means of which the blade E may be clamped in position relative to the leg B after being adjusted to the desired angle that is to be measured or laid out. The blade E is graduated and marked as a protractor, as shown in Fig. 1, so as to serve as a guide in adjusting the position of the leg B relative to the legAwhen using the device as a protractor. In practice I secure to the leg B a pin or projection 12, adapted to interlock with any one of the notches e 6 during the adjustment of the protractor. In the recess B is located a spring H, which serves to hold the blade E interlocked with the pin or projection b after the legs AB have been adjusted to the desired angle. However, as an additional locking means I use the set-screw G, above mentioned, for rigidly securing the leg B to the blade E after adjustment.

The device is very simple and can be used as an ordinary rule as well as a protractor whenever so desired. When used as a rule, the leg B is expanded sufficiently to cause the blade E to be disconnected therefrom, after which said blade is folded into the groove A in the legAinamanner like closing the blade of a j ackknife.

What I wish to-secure by Letters Patent and claim is-- The herein described combined rule and protractor consisting in combination with the jointed legs A, B, of a graduated protractorblade E pivoted to one of said legs and guided in and adapted to be secured in desirable position to the other leg, said protractor-blade having notches e, e, 6 adapted to interlock with a projection in the leg B, and a spring H for holding said blade in its adjusted position, and an adjustable binder-screw screwed through one of the legs against the protractorblade for rigidly securing the legs in any desired angular position as and for the purpose set forth.

In testimony whereof I have aflixed my signature in presence of two witnesses.

ALBERT PETERSON. 

